HeinOnline is a legal research database composed (mostly) of scanned print material so law review editors can assemble authoritative sources, including (most importantly)
Click here to access HeinOnline. Please contact the library is you have questions: lawlibrary@northeastern.edu
Generally, the correct source for non-Supreme Court decisions is a reporter published by West - Federal Reporter and Federal Supplement for federal decisions and the West regional reporter (not the state's official reporter) for state cases. Westlaw provides a pdf facsimile of decisions as reported in West reporters. Open the pdf by clicking the "Original Image" link in the top left corner of the decision.
The GPO produces PDFs with a digital watermark identifying that they are authentic and protected against alteration. Such "authenticated" documents are acceptable sources under Rule 18.2.
PDFs of recent issues of the Federal Register are available from Federalregister.gov.
PDFs of recent copies of the Code of Federal Regulations are available from www.govinfo.gov/app/collection/cfr
Older scans of the CFR and the Federal Register are available from HeinOnline.